Bhopal: Two notices, sent to former Union Carbide CEO Warren Anderson at his US addresses by a probe panel, were returned by the authorities concerned on the ground of "person unidentified and insufficient address", sources said on Wednesday.

The two notices were sent through the government of India to Greenwich and New York addresses of Anderson, but both were returned to the Union Carbide Poisonous Gas Leak Probe Commission headed by Justice (Retd) SL Kocchar, they said. However, undeterred by the return of these notices, the commission is again trying to serve the notice to Anderson through the Government of India, the commission said in a release.

The commission was constituted after a lot of hue and cry was raised over inadequate punishment awarded to the accused by a local court in June 2010. The panel also said that NGOs working for the welfare of Bhopal's gas affected people have also not appeared before the Commission to help it in the probe, it said.

The two notices were sent through the Government of India to Greenwich and New York addresses of the former CEO of Union Carbide.

A notice was also send to the then Hanumanganj police station in-charge Surendra Singh Thakur on September 21, but his statements were not recorded since he was abroad. The commission has fixed November 26 as the next date